What Is Heartburn?

Heartburn is one of the most common health conditions that people experience in today's society. It is thought that about 1 in 10 people suffer from daily heartburn and about 1 in 3 people suffer from heartburn at least once a month. Before talking about the symptoms and treatment for heartburn, it may be helpful to understand the normal digestive process and how certain conditions can impact this normal process, resulting in heartburn.

Normal Digestive Process
As you chew your food and swallow, food particles travel from your mouth to the esophagus. The esophagus is a muscular tube that contracts and relaxes in a wave-like motion to help move food and liquids down toward your stomach. This motion is called peristalsis.

Just before the esophagus gets to the stomach, it travels through your diaphragm. The diaphragm is a broad muscle that separates your stomach from your chest cavity. The opening in the diaphragm where the esophagus travels through is called the hiatus.

The esophagus then joins the stomach at the lower esophageal sphincter (LES). This sphincter acts as a doorway between the esophagus and the stomach. After you swallow, it opens to let food into the stomach. Then the sphincter closes to keep food and stomach juices from going back up into the esophagus. The hiatus also helps close off the entryway to the stomach.

Inside your stomach, strong acids and enzymes make up the stomach juices that break down your food. Your stomach has special mechanisms that help protect it from these strong juices.

Your esophagus, however, doesn't have these same defenses, so it's important for the LES to close off the stomach opening to keep the juices in the stomach. Sometimes, the acidic contents of the stomach do go back up, or reflux, into the esophagus. Some reflux is normal. Much of the time, this never causes any problems, because the esophagus also has some ways to protect itself. For example, the saliva in your esophagus can help neutralize stomach acid, and gravity and peristalsis help to wash the saliva and stomach juices back down into the stomach.

At other times, acid reflux can cause the burning, pressure, or pain in the chest or throat that most people call heartburn or acid indigestion.

Impact of Heartburn on the Digestive System
For people who have heartburn, the sphincter between the esophagus and the stomach either opens at the wrong time or is weak and doesn't completely close off the opening to the stomach. When this happens, stomach juices and food particles can flow back up into the esophagus more frequently than normal.

If stomach juices stay in the esophagus for long periods of time, or if acid reflux happens often, the natural way the esophagus protects itself from stomach juices may simply be overwhelmed. The lining of the esophagus may become irritated, and this can lead to heartburn.